Firing mechanism for use with a gun synchronizer



Nov. 2o, 1951 P. H. mxoN 2,575,411

FIRING MECHANISM FOR USE WITH A GUN SYNCHRONIZER Filed Oct. 9, 1946 2 SHEETS-SHEET 1 lZZ /4 6343686 P. H. vDIXON Nov. 20, 1951 FIRING MECHANISM FOR USE WITH A GUN SYNCHRONIZER 2 SHEETS-SHEET 2 Filed Oct. 9, 1946 Inventor Paul fi. Dixon Patented Nov. 20,Y 1951 .FIR-INGM-ECHANISMFOR USE WITH A GUN .SYNCHRONIZEB ,Pauli-I. Dixon, Springfield, Ill., assignor to United :Shoe Machinery Corporation,

Flemington,

N.,J., -a corporation of New Jersey t ApplicationOctober 9, 1946, Serial No.'702,129

(Cl. r89-133) l2 Claims. l p .AIhis .invention relates -to va 20mm. aircraft gunand particularly to the breech block assemblycf such..a gun.

.Itis-an object-.of the present invention-taim- Vprove. the breech block assembly so that a positive control may be obtained over the timing of the .ringpin which comprises -a part ofv the assembly.

Inaccordance ,with one -feature of theinven- .tion a sea-r releasing Vmember is mounted'to rock tin a slide v-key joining breech block slides for .a propellershaft whenthe gun is in battery.

In accordance with another feature `of the invention, latches are :provided which yprevent a rebound of the breech block slides.

In the drawings,

Fig. 1 is a plan view, partly in section, of a portion of the breech block assembly, including fa. ring pin and a sear, and shows also a trigger motor for actuatingthe sear;

' Fig.-2 is a'section on the line II-II of Fig. 1; Fig. 3-is asection on the line III-IIIof Fig. 1; Fig. 4 shows ya bolt with breech block slides mounted thereon;

.'Fig. 5is an exploded view ofthe sear, a vfiring pin support and bushing, and a breech Yblock slide .key with a sear actuating means; and

Fig. 6 is a plan view, partly in section, `of fa .fragment of the breech block assembly, showing the sear actuating means inthe position it assumes Aat theend of its actuating movement.

The inventionis illustrated as embodied in a `rwell-known vHispano Suiza 20 mm. aircraft gun -and only the gun parts needed for an understanding of the present invention will be described.v These parts mainly comprise the breech block assembly which is mounted in a receiver frame `III (Figs. land 3) of the gun. Included in the breech block assembly are a bolt I2 (Figs. .1, 3, and 4) and two breech block slides I4 :mounted on flanges I6 formed on-each side of .the bolt I2. =The slides I4 are joined'by'a slide .key I8 which passesthrougha transverse --slot l2l) (Figa 2 and 4) of the fbolt I2, the slot being somewhat longer than the width offthe-key IB in order to ypermit a movement of the breech block slides Ill relatively to the bolt I2 in a direction parallel to the longitudinal axis of the gun.

.A central bore 22 (Fig. l) of thebolt 2 is machined so as to accommodate thegun Viiring parts which also form a portion of the breech block assembly. Included in the gun iiring parts is a-ring pin support 24 (Figs. l and 2) held in ffixedposition in the bore 22 by a retaining pin T26. The forward end of the support 24 engages ;a bushing :28 which abuts a seat 35) formed'inthe 'bolt at theiorward end 'of the bore 22. Mounted 2 in the firing pin support 24 and bushing 28.for movementtherewith as well as relative thereto. longitudinally of thebolt, is a firing pin 3'2. The ring pin 32 is actuatedby two springs 34, 36 which surround the rear portion of the firing pin between an annular projection 33 of the pin 32 and a retaining plug 4l). The retaining plug 4U is held in i'lxed position in the-bore 22 of the bolt I2 by a locking pin L52 which extends through the bolt I2. When the ring pin 32 is released to effect firing of the gun, the reduced forward end of the firing pin moves through a passage 43 extending forward in the bolt I2. from the center of the bore 22.

The firing pin `32 is initially held locked inits cocked position, preparatory to the ring, by va scar 4I! (Figs. l, 2, 3, and 5) which engages a shoulder-I6 on the `firing pin 32. VThe sear 44 is movably mounted in the firing pin support 24 (Figs. 1 and 5) and is maintained in a position to lock the firing pin 32 by a leaf spring i8 (Figs. V2v and 3) seated at its opposite endsabove the sear in a groove 50 of the bolt I2 and engaging the sear with its midportion.

In order to release the ring pin 32 in accordance with the present invention, the sear 44 is moved `upward against the pressure of its spring by a novel -sear actuating or tripping member -52 mounted to rock in agroove provided in the slide key I8 about an axis extending Ytransversely of the bolt I2. Rockingmovement is imparted to the member 52 by a slide 54 which moves transversely of the bolt in a guideway of the slide keyI, as shown in Fig. 5, a camface 56 (Fig. 3) on the inner end ofthe slide'54 acting on an inclined face `58 provided on a projection -g 'ofthe tripping member 52.

The slide 54 is moved inward to act on the fmemberi52 by a `known trigger motor 30 (Figs. l and 3) secured to a mounting plate 62 which is carried -by a bracket 64 (Fig. 3) attached, in turn, to a gun cradle E6. The bracket 64 is `so'located on the cradlewIS that the trigger molftor AIIJ is ina position to act on the sear slide "54 when the gun is in its battery position ready to befred. As has been indicatedgthegun with zwhich the trigger motor SI5' is used as an aircraft gun-intended to `operate in synchronism with the propeller shaft of the airplanein which the gun is mounted. An impulse generator (not shown) operated by the propeller shaft trans- '.mits impulses to the trigger motor t!! to move-the mounted in the motor housing 68.y The inner end of the slide 16 is positioned immediately opposite the outer end of the sear slide 54, as shown in Figs. 1 and 3, when the gun parts are in their battery positions. Thus, inward movement of the motor slide 16 serves to effect an inward movement of the sear slide 54. Moreover, the slide 16, when moving inward, compresses a spring 18 mounted in a recess of the motor housing 68 between a projection near the outer end'of the motor slide 16 and a wall of the housing 68. The springs 12, 18 return the trigger motor parts to their initial impulse receiving position upon firing of the gun. Y Y

The trigger motor 60 may be used either on a left-hand or a right-hand gun and is merely secured to the gun cradle 66 at the appropriate gun side. Two sear slides 54 may be provided,'one mounted at each side of the slide key I8 in order that the improved breech block assembly may be utilized both in left-hand and right-hand guns without requiring any interchanging or substituting of any breech block assembly parts.

In order to prevent a rebound of the breech block slides I4 at the end of the counterrecoil movement of the gun, each slide is provided with a slot 88 (Fig. 4) in which a latch 82 is mounted for movement relatively to theslide, the latch 82 having a pivotal connection 84 (Fig. l) with the slide at the forward end of the slot 88. The rear portion of each latch is'periodically forced into engagement with a cooperating locking face 86 on the bolt I2 by a plunger 88. The plungers 88 have a sliding movement parallel tothe longitudinal axis ofthe bolt I2 in blocks 98 which are mounted in the rear portions ofthe slots 88 and may move slightly relatively to the slides I4 in the said slots 80. Normally, the plungers are held in their outer positions relatively to the blocks 98 by springs 92 seated in the blocks behind the plungers, the extent f plunger movement being determined by pins 94 which extend through the blocks 98 and engage in longitudinal grooves 96 in the plungers 88.

Assuming that the gun parts are in their battery positions, the improved breech block as- When the trigger sembly functions as follows. motor 60 (Fig. 1) receives an impulse from its generator, the plunger 18 moves to the left (as seen in Fig. 1) compressing the spring 12 and moving the slide 16 inward against the pressure of the spring 18. The trigger motor slide 16 acts on the sear slide 54 and forces it inward (Fig. 3) said slide 54, through its cam face 56, rocking the tripping member 52 thus moving the sear 44 (Fig. 2) upward out of locking engagement withthe shoulder 46 of the ring pin 32. This releases the firing pin 32 and permits the springs 34, 36 to move the ring pin forward, i. e., to the left, as seen in Figs. 1 and 2, to fire the gun. The trigger motor parts are then returned to their initial positions by the springs 12, 18.

As the gun parts move in recoil, i. e., to the right as seen in Figs. 1 and 2, under the action of expanding gases produced by the explosion of the propelling charge, the breech block slides VI4 are first moved rearward in known manner to unlock the breech block assembly. The bolt engaging portions of the latches 82 and the locking faces 86 of the bolt I2 are so shaped that the latches 82 will be cammed out of locking engagement with the bolt I2 by the initial rearward movement of the slides I4, the force of the slides overcoming the pressure of the springs 92 so that the latches force the plungers 88 inward into their blocks 98.

4 yDuring 'this initial rearward movement of the slides I4 the key I8 is moved therewith relatively to the bolt I2. In thus moving, the key I8 engages the shoulder 46A of the firing pin 32 and moves the firing pin rearward, simultaneously compressing the springs 34, 36. WhenV the shoulder 46 of the firing pin 32 has moved rearward beyond the sear 44, the spring 48 forces the sear downward into locking engagement with the shoulder 46 (Fig. 2), thus holding the firing pin in its cocked position. A cam face 98(Fig. 6) formed within the slot 20 of the bolt I2 acts on the sear slide 54 during the relative rearward movement of the key I 8 and returns the sear slide 54 to its outer position. The bolt I2 thereupon also moves rearward inY recoil and at the end of that movement the breech block assembly parts again move forward, or to the left as seen in Figs. 1 and 2, in counterrecoil.V 1

The plungers 88, under the pressure of their springs 92, seek to swing the latches 82 inward (Fig. l) into engagement with the bolt I2 upon return of the bolt to its battery position. As the slides I4 reach their battery position, the blocks 96 continue to move forward slightly in the slots (Fig. 4) so that the plungers 88 maintain the latches 82 in engagement with the lockingffaces 86 of the bolt I2 and prevent the slides from rev bounding. The parts of the breech block assembly have now regained their initial or batterypositions.

Having now described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In an automatic gun constructed and arranged to operate in synchronism with the prog peller shaft of aircraft and to move in recoil and counterrecoil, a reciprocating Ybreech bolt having a bore, a firing p'm support secured in the bore of the breech bolt, a firing pin mounted for movement between cocked and ring positions in the support, springs for moving the firing pin to its firing position, breech block slides guided for movement on the'breech bolt during the recoil and counterrecoil of the gun, a key J'Oined to the breech block slides and engageable with the ring pin to move the firing pin to its cocked position against the action of the ring pin springs during recoil ofthe gun, a sear movably mounted in the firing pin support, a sear spring mounted in the breech bolt in engagement with the sear and tending to move the sear to lock the firing pin in its cocked position, a seartripping member mounted to rock in the slide key, and a power operated sear slide movable in the slide key to rock the sear tripping member when the gun is in battery.

2. In anautomatic gun of the type defined in REFERENCES CITED l The following references are of record inthe file of this patent;

UNITED STATES PATENT Number Y Name Date 1,750,706 CouplaltldY Mar. 18,V 1930 1,770,125 Coupland July 8', 1930V A 2,159,126 Bilkgt May 23, 1939 2,411,290 Pontius Now/".19J 1948 

